Pusher



Nov. 24, 1 w. P. GALLEN 2,914,331

PUSHER Filed Oct. 24, 1956 2 Sheets-Sheet 1 INVENTOR. W/L L /A N f- GALLF/V ATTORNEYS Nov. 24, 1959 w. P. GALLEN 2,914,331

PUSHER Filed Oct. 24, 1956 2 Sheets-Sheet 2 v INVENTOR. W/Z L IAN PGAZZE/V A TTORNEYS United States Patent PUSHER William P. Gallen, North Royalton, Ohio Application October 24, 1956, Serial No. 618,008

7 Claims. (Cl. 27950) This invention relates to stock pushers or feeders or stock feeding collets, as the same are called variously, for automatic screw machines and more particularly to improvements in and upon the inventions contained in my prior Patents Nos. 2,299,972 and 2,513,557.

While pushers following the teachings of my prior patents brought to the art the advantages related to those patents, experience discovered new problems impairing the most full realization of those advantages. For example, my prior pushers were found to sometimes suffer injury to the bayonet locking lugs or ears at the foremost end of the shell from encounter with, or incident to feeding, the end of the last increment of stock. My prior pushers also left not entirely solved the problems of having, selectively, a high drag and initial grip by hard pads for feeding long heavy bars of hard stock, at one extreme condition, and a light grip by soft pads on short light bars of stock, at the other extreme condition. lntermediately were the conditions of deriving a high drag and initial grip between soft pads and long lengths of easily scratched stock. Experience with my prior pushers also developed the need for a greater facility by the pusher for handling hexagonal and other noncircular stock, both in accepting new bar at the rear end and in feeding the last increments at the front end.

A general object of my present invention is to solve the problems found in and discovered in connection with the use of my prior pushers and to extend the advantages and potential advantages of the inventions patented in my prior patents.

It is among the more specific objects of my invention to provide a stock pusher having the advantages of my patented pushers but also having (1) inherent invulnerability against injury from engagement with the last end of the stock being fed to the driving collet, (2) the ability to accommodate hex or other non-round stock particularly in machines where the pusher and collet sleeves are held against relative angular displacement, (3) a determinable adjustable grip and drag upon the stock regardless of the temper and/or in wear of the pad pushing ring, (4) utility with brass or other soft pads and bushings to avoid scratching or scoring soft metal stock, and (5) adjustable spring tension on the foremost end of the stock engaging bushings coacting with the cam actuation of my prior patents so that extra tension may be provided for extra long bars and compensation may be had against wear of the stock engaging pads.

Other objects and advantages will appear from the following description of a preferred form and a modified form of my invention, reference being had to the accompanying drawings in which:

Figure 1 is a side elevation of my pusher with a portion of the shell element broken away and with a phantom representation of the load or stock to be pushed or fed.

Figure 2 is a transverse section taken along the plane of the line 2-2 of Figure l.

' ice Figure 3 is a transverse section taken along the plane of the line 3-3 of Figure 1.

Figure 4 is an end elevation of my pusher taken from the right end as viewed in Figure 1 but in the absence of any load or stock engaged thereby.

Figure 5 is a perspective view of one of the main operating springs showing the preferred form or shape thereof before being attached to the bushing.

Figure 6 is a longitudinal sectional View of the outer shell element of my pusher.

Figure 7 is an end elevation of the shell viewed from the right of Figure 6.

Figure 8 is a longitudinal section of the bushing and pad element of my pusher.

Figure 9 is an end elevation of the bushing of Figure 8 as viewed from the left end.

Figure 10 is an end elevation of the bushing of Figure 8 viewed from the right end.

Figure 11 is a fragmentary longitudinal section of a bushing similar to the bushing of Figures 8, 9 and 10 but having the pad surfaces formed to engage hexagonal stock.

Figure 12 is a left end elevation of the bushing of Figure 11, and

Figure 13 is a right end elevation of the bushing of Figure 11.

Following the teachings of my prior patents my presently improved pusher comprises in this preferred form an outer hollow cylindrical body or female member, conveniently called the shell 1, and an inner stockgripping, male member, conveniently called the bushing 20. In their general operation, arrangement and disposition these parts follow the teachings of my prior patent particularly in that when the parts are assembled as shown in Figures 1, 2 and 3, the bushing is disposed within the major cylindrical bore 2 of the forward, or right end as viewed in Figure 1, of the shell, and is constrained against unlimited rotary motion with respect thereto, and has freedom for limited relative longitudinal and/or reciprocatory motion therein whilst the cams 26 of the bushing have sliding contact and engagement with the conically inclined cam surface 7 of the shell and are forced radially inwardly as the bushing is induced to move longitudinally inwardly of the shell to enhance the grip of the bushing (and the pusher as a whole) upon the stock S, and conversely to reduce the grip upon the stock when the opposite relative movement takes place. When the bushing is gripping stock or otherwise expanded to its maximum normal working size its external cylindrical walls have a free sliding fit within the bore 2 of the shell.

As is known in the art and mentioned in my prior patents the shell 1 is secured to a feeding spindle, not shown, of the automatic machine in which it is employed by a threaded connection through the threads T at the rearward end of the shell, i.e., the leftward end as viewed in Figures 1 and 6, and the pusher as a whole is moved bodily forwardly during the stock feeding stroke of the machine wherewith to advance the stock S that passes through the pusher as a whole and particularly through the interior of the bushing where it is engaged by the internal gripping surfaces G of the pads 22 of the bushing. It is characteristic of my patented pusher that the grip upon the stock is enhanced by the cam relationship above mentioned on the feeding stroke wherewith the stock is firmly carried forward and held against the stop of the machine until the driving collet of the machine grasps the proper length of stock exposing the proper length of the part thereof to be worked upon for the working cycle of the machine. Thereupon retraction of the feeding spindle acting on the shell 1 directly, and indirectly upon the bushing 20', releases the cams and withdraws the pusher rearwardly along the stock with a diminished grip thereupon to a rearward position from which the feeding stroke and cycle is re-initiated.

Also, each different size and shape of stock requires an appropriate and particular size and shape of gripping surface in the pusher to coact therewith. Cf. Figures 8-10 and 11-13. In the past, excepting my prior patents, it has been common practice to change pushers as a whole with each change of stock; that is, the .pushers or so'called feed fingers have had to be removed bodily from the feed spindle and replaced by different ones adapted to the new stock. Following the teaching of my prior patents, I provide that only the bushing or stock gripping part need be replaced to accommodatea change in stock. As will more fully appear below I have retained the general principle ofa bayonet lock connection between the shelland bushing.

Prcferring to follow the teaching of my prior patents, where the same is not inconsistent with the instant invention the shell 1 has a longitudinally extending slot 4, Figures 2, 6 and 7, leading from its forward end through and beyond the zone of its camming surface 7 wherewith to permit the shell to yieldingly avoid bursting in the event the pressure between the cams 25 and the surface 7 tends to become excessive. The shell 1 also comprises at its forward end the bifurcated arrangement of overhanging lugs or extensions 3 each comprising a little less than a quadrant in circumferential extent and functioning as the female parts of a bayonet lock overhanging the earns 26, see Figures 1 and 4, when the bushing has been inserted into the forward end of the shell and turned 90 wherewith to register the earns 26 behind the lugs. The earns 26 correspondingly are of less than 99 in circumferential extent, Figures 9 and 12, wherewith to facilitate the entry of the bushing into the forward end of the shell when thebushing is held withthe earns 26 at right angles to the lugs 3. As shown in Figures 6 and 8 and as taught in my prior patents, the forward faces 27 of the earns 26 are preferably inclined rearwardly from the radial plane to coact with complementarily inclined cam surfaces 3 on the rearward faces of the lugs 3 so that engagement between these surfaces on the rearward stroke of the pusher will tend to expand or at least not contract the bushing. In the operative relation of the parts the maximum diametrical span of the earns "26 exceeds the minimum diametrical span between the inner surfaces of the lugs 3 wherewith the parts are retained in the bayonet locking relationship taught in my prior patents.

The shell 1 has its minor rearward cylindrical bore 9 smaller than the bore 2 but of a diameter large enough to permit the free movement therethrough of stock of maximum capacity leaving a relatively thick walled portion of the shell in the rearward part thereof which terminates in a shoulder against which are selectively disposed as few or many rings 10 as may be desired to act as an adjustable stop against which the rearward end of the bushing 29 abuts at the limit of its extreme longitudinal inward movement. As taught in my prior patents the shell is preferably made of appropriate quality of steel susceptible of being freely machined to give it the configuration described and also susceptible of being hardened in the zone of the cam surface 7 adjacent its forward end but also tempered to a desirable degree of resiliency rearwardly of the cam surface 7 and particularly throughout the zone of the slot 4 wherewith to combine both desirable wear resistant characteristics in the cam surface and desirable resilience of the adjacent structure to permit the expansion of the cam surface 7 under at least extreme load.

The bushing follows more the teaching of my prior Patent No. 2,513,557 in recognizable respects including its general coaction with the shelland in'its general-form and contour, with-stock gripping pads 22 relatively ,n1ova-' ble radially with respect toeach other wherewith to'grip' the stock along the internal gripping surfaces G thereof. The bushing 20 integrally includes a rearward ring portion 21 integrally joined by diametrically opposed and spaced parts 32 to the pad portions 22 wherewith to give the pads an inherent tendency to have an initial resilient grip upon the stock to be pushed prior to receiving aid from the action of the bushing earns 26 on the surface cams 7 of the shell. The longitudinal lengths of the resilient ring 21 may be proportioned to the length of the pads 22 about as shown in the drawings, and the circumferential lengths of the parts 32 may also be proportioned as shown having regard for the desired resilient strength sought from the ring 21 and the parts 32. It is desirable, however, that the thickness of the ring 21 shall not materially impair the capacity of the pusher with respect to the maximum diameter of the stock to be fed thereby. Similarly the radial dimensions of the pads along with the shape of the gripping surfaces G may be accommodated to a wide variety of shapes and sizes of stock up to the point where the thickness of the pads does not substantially exceed the thickness of the ring 21. In these forms of bushings in which the pads 22 are thicker than the ring 21 I prefer that the rearward ends of the pads merge into the ring in a chamfered or conical junction 25 between the ring and the pads whereby to enhance the strength of the bond therebetween as well as to afford a guide for the end of the stock to be received therein. As shown in the drawings, except Figures 11-13, inclusive, the pads 22 are thickened with the surfaces G cylindrical in form wherewith to engage round stock of smaller diameter than the largest size stock that might be accommodated in a pusher combination comprising the sarne shell v1 and a different internal size of bushing with thin pads having the gripping surfaces G correspondingly enlarged. The bushing as a whole is preferably made of that kind of steel in which the pads and particularly the gripping surfaces G thereof may be hardened for the sake of long wear and the ring portion 21 and parts 32 thereof may be appropriately spring tempered wherewith to give it the desired resiliency for the purposes above described. I do not exclude other materials that may be used to better advantage with regard to the different kinds of stock upon which my pusher may operate that retain the essential characteristics and mode of operation thereof explained in my prior patents and of the instant improvement. As more fully explained in my prior patents, it is advantageous to have in mind that the qualities of the material of the bushing and the shell and the hardness or relative hardness of the parts that have the camming action on the one hand and the stock gripping function on the other hand bears upon not only the wearing qualities of such parts but the co-eflicient of friction of such parts in relation to each other and to the stock to be pushed. Due regard for these considerations for their bearing upon the inclination of the camming surface 7, the contour of the faces of the earns 26 and the quality and hardness of the parts with regard to the form, shape and quality of the stock to be pushed will be had by those skilled in the art within the teachings of this specification and my prior patents.

Referring particularly to Figures 8, 9 and 10, the pads 22 of the bushing 20 are preferably approximately semicylindrical (for round bar stock) and are separated for relative movement toward and away from each other by longitudinally extending slots 30; the slots extending rearwardly of the bushing as far as the ring portion 21 and terminating on one side at least, the side shown in Figure 8, in an enlarged aperture 31 having a circumferential extent preferably a little greater than 60 and appreciably less than The aperture 31 has, as shown in Figure 8, a considerable longitudinal dimension related to the extent of the longitudinal motion desired to be had between the bushing and the shell as selectively limited by the number of rings 10 bearing on the shoulder 5 ol'.

the shell as between earns 26 and lugs 3. The slot 30 on the opposite side of the bushing may have a prudently rounded terminus, not shown, opposite the aperture 31 which, if desired, may be engaged with tab 13 of the retaining spring clip 12 when little or no angular motion is sought or desired to behad between the bushing and shell.

When the tab 13 is disposed in the aperture 31, Figure 2, and permits about 60 angular motion between the bushing and shell, a nice advantage follows in connection with the feeding of hex stock, for example: In some automatic screw machines the sleeves for driving and moving the driving collet and feeding pusher are restrained against relative angular motion. When non-circular stock is to be fed, and the advantage of using complementary pads in the pusher is desired, the non-circular pad of the pusher must be angularly aligned with the non-circular pads of the collet, else the stock will be mistakenly gripped and/or scuffed or scratched at one or both places. Heretofore alignment was accomplished by shimming or grinding the shell adjacent the threads T so the shell threads would bottom in the sleeve threads at the desired angular position of the pad. With my present improvement the shell and sleeve may take most any angular relation and the pads of the bushing will line up with the pads of the collet by virtue of the freedom of the bushing to rotate in the shell withinsuch limits as I have mentioned above.

It is within the teaching of my present improvement to follow the teaching of my prior Patent No. 2,513,557 and harden the pads 22 and spring temper the rearward parts of the bushing, ring 21 and connecting portions 32, while the forward ends of the pads are in direct contact as suggested in Figure 4 whereby the pads will have to be sprung apart against the resilience of the rearward parts of the bushing when bar stock is forced into the rear ward end-of the bushing. Such a bushing will have essentially one desired measure of initial frictional grip and drag on the stock to induce the secondary gripping by the camming action between the cams 26 and surface 7. But my present invention also comprehends that the ring portion 21 and the connecting portions 32 may contribute little or no spring gripping force to the pads; being either left soft after the pads have hardened or being of low resilience when the bushing as a whole is made of relatively soft or non-resilient material for the sake of having relatively soft pads to prevent the scratching of soft or highly finished bar stock. That is to say, according to the preferred operation of my present improvement the ring 21 serves more as a fulcrum for the pads 22 than as a motivating resilient force as in my prior patents. As shown in Figures 8 and 11, I prefer that the cams 26 be disposed more nearly the rearward ends of the pads 22 than in my prior pushers since as will presently more fully appear much of the operation of' my present invention is related to the constriction of the pads 22 upon the stock by the spring N, Figures 1, 3 and 5, disposed upon the forward end of the bushing and forcibly constricting the pads in the direction to close the gaps 30 and forcibly engage the stock S.

In my present improvement the frictional grip of the pads upon the stock may be partly or not at all supplied by the ring 21 and connecting portions 32 of the bushing, but will preferably be partly or exclusively supplied by the spring N acting on the extreme forward end of the bushing. As taught in my prior patents the ultimate grip of the pads upon the stock during the feeding stroke of the pusher is a combination of the resilient grip of the pads upon the stock augmented by the cam action of U the conical cam 7 of the shell on the cams 26 of the bushing. According to the teachings of my prior patents the gripping force from the cams may be selectively con-' trolled by limiting or admitting less or greater longitudi-' nal motion between the bushing and the shell: In the present instance as by placing a greater or lesser number of rings 10 between the shoulder 5 of the shell and.

the rearward end of the bushing; the fewer the rings 10 the greater the longitudinal motion and the greater squeezing force exerted by thecams, and vice versa. In the present improvement I am also able to modify and selectively control the resilient grip and/ or drag of the pads upon the stock by selectively and removably applying weaker or stronger springs N to the forward end of the bushing. By the choice of such springs I control the resilient grip as well as the cam action for any given combination of shell and bushing. As shown particularly in Figures 1, 3, 8 and 11, the selected spring N is removably disposed in a groove 14 near the forward end of the bushing; the forward wall 15 of the groove 14 preferably having a sloping configuration to facilitate the application and removal of the selected spring N to and from thebushing.

Depending on the size, quality and finish of the stock to be pushed, it is my teaching to provide a plurality of springs N of different thickness and different strength,

such that for a pusher with a 1%" OD. shell, a plurality of springs N varying in strength and thickness by small increments from A to about 7 may be selectively applied to the forward end of the bushing to give it widely varying degrees of drag and resilient grip upon the stock. Preferably the springs N are shaped to an elliptical form as suggested in Figure 5 and applied to the end of the bushing to exert their greatest strength transversely of the plane of the slots 30. By the use of the correctly selected light spring N and using a dead soft bushing, and so many rings 10 that but little camming action is brought into play, a very delicate drag and ultimate working grip upon highly finished lightweight stock may be had, for example of one extreme condition. The initial drag for such a bushing may be increased up to the strength of a selected very stout spring N: the cam action increased by removal of rings 10. For the maxi mum stoutest grip upon the heaviest toughest stock to be pushed, the bushing may be selected for its hardness and toughness, the number of rings 10 reduced or eliminated whereby to gain the greatest longitudinal motion and camming action between the bushing and the shell, and the heaviest and toughest spring N applied to the bushing. Good spring steel is appropriate material for the springs N. The work of the springs N permits the wider selection of materials for the bushings and pads than was practicable under the teaching of my prior patents.

As I have shown in Figure 1, the forward end of the bushing 20 is disposed to lie largely forwardly of, i.e.,,

out in front of, the forward end of the shell 1 and well in front of the lugs 3 of the shell 1. I also prefer that the outside diameter of the extreme forward end of the bushing be but little less than the outside diameter of the shell when the bushing is fully expanded to accept the stock S to be pushed. I also prefer that the depth of the channel 14 in the forward end of the bushing be such that with the thickest and stoutest of the springs N that the outside diameter of the spring when fully expanded by acceptance of full size stock in the pads 22 will be only. slightly less than the outside diameter of the shell. Comparing Figures 1 and 8, it will be noticed that much of the longitudinal extent of the pads 20 lies forward of the cams 26, the opposite halves of the bushing being loaded by the cams somewhat as a beam loaded in the middle and supported at its ends albeit the inherent flexibility of the rearward portions of the bushing tend to yield to let the pads have full length engagement with the surface of stock to be pushed.

The disposition of the front end of the bushing Well out in-front of the front end'of the shell protects the lugs 3 of the shell from those injuries which I found-occurring increment of stock was being fed and/or had been fed so that the free end of' the stock, free of the grip of the pads of the pusher, could strike the lugs and injure the latter. By my present improvement the front end of the pusher comprises entirely the stout substantially destructionproof front end of the bushing which shields all the other parts and portions of the pusher from the tail end of the last increment of a bar that has been or is being fed, should the same not be gripped by any portion of the pads 22.

In Figures ll, 12 and 13 the bushing 20 may correspond in all respects to the bushing 29 excepting that the pads 23 are given non-circular, hexagonal for example, form throughout the greater and rearward portion of the length thereof, see Figure 12, but are given circular form as at 24, see also Figure 13, of diameter corresponding to the major diameter of the hex, throughout the forward and preferably lesser portion of the pads, substantially as shown. More particularly, the longitudinal extent of the circular cylindrical portion of the pads 23 is preferably given a longitudinal dimension approximately corresponding to the overtravel of the pusher so that the last end of a bar of stock being fed can enter the bushing to the extent of overtravel without having to register in alignment with the pads. Or put the other way, the hexagonal or other non-circular portion of the pad area, i.e., the real working portion of the pad area for stock of the same shape, is more nearly and fully back underthe cams so the radial forces therefrom will be most direct and significant and so that the last end of the stock may get out of angular register with the pads without injuring the stock and without tending to overexpand the bushing or pusher by malregistration.

The springs N are preferably of considerable less circumferential extent than 360 so that their ends will never tend to contact when the pads of the bushing are in their most constricted and/or worn working relation. 7 The rings are easily detached from and applied to the bushing with the familiar expansion type of pliers having their outer foremost edges adapted to hook under the ends of the springs and thereafter expand the same'for easy removal or attachment.

As compared with my prior pushers I find it practicable and advantageous to compensate for a considerable measure of wear of the pads in my pusher by removing a first selected spring N appropriate to the operation of my invention in the first instance and substituting stouter springs N to compensate for wear of the pads so that a particular bushing may be used through a greater wearing life than was practicable when the whole of the resil-' ient grip of the pads was supplied by the constant force of the tempered rearward portion of the bushing.

While I have illustrated and described a preferred and a modified form of my invention, other modifications, changes and improvements thereupon and therein will occur to those skilled in the art who come to understand and admire the precepts and advantages of my invention. Therefore I do not care to be limited in the scope of my patent to the form or forms of my invention herein specifically illustrated and described nor in any manner inconsistent with the progress which my invention has promoted the art.

I claim:

l. A stock feeding pusher comprising an outer shell member and an inner stock engaging bushing member, both members having mutually coacting cam surfaces and having free clearance apart from said cam surfaces and having freedom for longitudinal motion to induce stock gripping action between said carn surfaces, said shell member having its cam surfaces adjacent its forward end and said bushing having its cam surfaces of short longitudinal length in a longitudinally median portion and having a forward portion extending beyond the forward; end of the shell, said bushing having relativelymovabler stock gripping pads underlying said camsurfaces'and: extending from thereunder toward the forwardgend ofthe bushing, means at the rearwardend'of said bushingfor resiliently connecting and yieldably spacing said pads and. permitting rocking motion about said cam longitudinallyi means at the forward end of said bushing for resiliently: urging said pads toward gripping engagement with the stock to be pushed, and means selectively restraining relative longitudinal motion between said'members for selec-. tively apportioning said cam action in relation to said resilient urging.

2. A stock feeding pusher comprising an outer shell member and an inner stock engaging bushingmember, both members havingmutually coactingcam surfaces and having freedom for longitudinal motion to induce stock gripping action between said cam surfaces, one of said members having its cam surfaces curved in longitudinal section for limited longitudinal contact with the cam surfaces of the other member, said shell member having its cam surfaces adjacent its forward end and said bushing having its cam surfaces in a longitudinally median portion and having a forward portion extending beyond the forward end of the shell, said bushing having relatively movable stock gripping pads underlying said cam surfaces and extending from thereunder toward the forward end of the bushing, means at the rearward end of said bushing for yieldably spacing said pads and admitting longitudinal rocking motion thereof about said cam contact as a fulcrum, means at the forward end of said bushing for selectively resiliently urging said pads toward gripping engagement with the stock to be pushed, and means selectively limiting relative longitudinal motion between said members for selectively modifying said cam action.

3. A stock feeding pusher comprising hollow open ended male and female members having mutually coaeting cam surfaces tending to constrict said male member into stock gripping engagement upon relative movement between said members in the direction of entry of said male member into said female member, said male member comprising separate pad portions relatively movable radially under the influence of said cams and connected together at a rearward portion thereof interiorly of said female member and rearwardly of said' cam surface, said cam surfaces having limited longitudinal contact and supporting said pads for rocking motion thereabouts, said female member having spaced retaining lugs at its front end and having an internal abutment rearwardly of the rearward portion of said male member, at least one ring removably disposed between said abutment and said male member and selectively limiting the entry of said male member into said female member, said male member having a grooved portion of diameter approximately as great as the outside diameter of said female member and disposed outside of and in front of the front end of said female member, and a split resilient ring disposed in said groove tending to constrict said pad portions toward each other, said forward portion and said ring shielding said retaining lugs from any end of any stock engaged by the front end of' said pusher'and beingprevented from contacting said lug by said ring.

4. A stock feeding pusher comprising male and female members having mutually coacting cam surfaces tending to constrict said male member into stock gripping engagement upon relative movement between said members tending to induce entry of said male member into said female member, said male membercomprising separate non-circular pad portions relatively movable radially under the influence of said cams and connected together at a rearward portion thereof interiorly of said female member and rearwardly of said cam surface, said female member having arcuately spaced lugs at its front end retaining said male member within said female.

member throughout approximately 90 of angular displacement and means restraining said members from relative angular displacement beyond 90 While permitting lesser angular displacements to permit said pads to align angularly with non-circular stock.

5. A stock feeding pusher comprising inner and outer relatively longitudinally movable members in bayonet locked relationship admitting however longitudinal motion therebetween, said outer member having diametrically opposite lugs at its forward end participating in said relationship and having an inner shoulder spaced from said forward end, a selective plurality of rings bearing against said shoulder and engageable with the rearward end of said inner member, said inner member having a forward portion extending forwardly beyond the forward end of said outer member and beyond said lugs and having a greater diameter than the diametric Spacing between said lugs, and resilient means carried by said forward portion and tending to squeeze said inner member into resilient engagement with stock to be pushed, said rings preventing contact between said portion and said lugs.

6. In a stock feeding pusher having an outer shell member adapted to be forcibly actuated to feed stock and an inner stock engaging bushing member, both members having radial freedom and freedom for relative longitudinal movement and having mutually coacting cams tending to constrict said bushing member and expand said shell member when said bushing member is moved relatively to greater depth into said shell member, said shell member having arcuately spaced lugs at its front end admitting therebetween arcuately spaced cams on said bushing member and coacting with said cams to prevent Withdrawal of said bushing member when said cams and lugs are not angularly displaced from alignment, said bushing member having a rearward part comprising an annular resilient ring and a middle part including said cams disposed within said shell when said members are in operative relationship and having a portion extending forwardly beyond the front end of said shell member, said forwardly extending portion having at its foremost end an external diameter substantially as great as the external diameter of said shell and longitudinally spaced from said lugs and protecting said lugs from injury or contact with the end of any stock engaged by the front end of said pusher, and means restraining said members from angular displacement suflicient to permit said withdrawal while permitting angular displacement to accommodate pushing non-circular stock.

7. In a stock feeding pusher having an outer longitudinally movable shell member adapted to be forcibly actuated to feed stock and an inner stock engaging bushing member, both members having relative radial freedom and freedom for relative longitudinal movement and having mutuallycoacting cams bearing in limited longitudinal contact and tending to constrict said bushing member and expand said shell member when said bushing member is moved relatively to greater depth into said shell member, said shell member having arcuately spaced lugs at its front end admitting therebetween arcuately spaced cams on said bushing member and coacting with 'said cams to prevent withdrawal of said bushing member when said cams and lugs are aligned, said bushing member having a rearmost annular resilient part and a middle part including said cams disposed within said shell when said members are in operative relationship and having relatively radially movable stock gripping pads joining said resilient part and extending forwardly from said cams and having a large forward portion extending forwardly beyond the front end of said shell member, said forwardly extending portion having at its foremost end an external diameter substantially as great as the external diameter of said shell and longitudinally spaced from said lugs and protecting said lugs from injury or contact with the end of any stock engaged by the front end of said pusher and having a groove, a split resilient ring removably disposed in said groove urging said pads toward stock gripping relation, and means for selectively limiting the movement of said bushing into said shell.

References Cited in the file of this patent UNITED STATES PATENTS 2,299,912 Gallen et a1. Oct. 27, 1942 2,362,494 Martin Nov. 14, 1944 2,363,890 Martin Nov. 28, 1944 2,366,923 Martin Jan. 9, 1945 2,479,074 Martin Aug. 16, 1949 2,513,557 Gallen July 4, 1950 2,595,828 Cox May 6, 1952 2,749,135 Little June 5, 1956 

